The problem of Free Will isn’t really my bag, even though the Florida State University philosophy program is highly ranked in the area. But I do know one thing: the existence of free will doesn’t entail the falsity of materialism. So when we find evidence that even lowly insects show signs of free will, this can’t be taken as a sign that Darwinism is false.
The mistake we find in this post on Uncommon Descent starts here:
Though many Darwinists shy away from the implications of their beliefs as they apply to ascribing responsibility for human behavior, their position demands that all behavior is determined by the genetic heritage of selfish genes.
This is simply wrong. Darwinism only entails that all of our genetic inheritance (our genotype) is due to natural processes, the most important of which is natural selection. Our physical structure, with hands, feet, brains and so on (our phenotype) is at least partially influenced by our genotype. To say that “all [our] behavior” is determined by our genes requires more than a Darwinian account of the origins of our genes. For this further claim to be true, it needs to be that our mental structures are wholly determined by our genes and that our behaviors are wholly determined by our mental structures, much like the route of a train is wholly determined by the placement and orientation of the track on which it runs.
But this isn’t part and parcel of Darwinism. There is no “demand” that we move from Darwin to behavioral determinism. There are some Darwinians who accept the move, but there are also Darwinians who reject that move; I know, because I am one. But neither camp thinks that Darwinian natural selection entails behavioral determinism. To think that there is behavioral determinism is to think further things about the structures of our brain, the influence of neurons on behavior, and so on.
So to say:
But if free will exists in flies, can it be denied in humans?
… is, I think, true. But it doesn’t imply the following:
If free will in fact exists, it must exist outside the deterministic universe of materialism.
If free will in fact exists, this simply shows that it most likely has a Darwinian origin, due to selection pressures. If free will exists — and I think that it does — and if Darwinism is true, then free will is compatible with Darwinism. To say otherwise is to simply beg the question — to assume that free will is only free if it was a gift from God.